Alkyl aryl sulfonate detergents



United States Patent 3,234,297 ALKYL ARYL SULFONATE DETERGENTS CharlesA. Cohen, Westfield, N.J., assignor to Esso Research and EngineeringCompany, a corporation of Delaware No Drawing. Filed Mar. 28, 1960, Ser.No. 17,796

The portion of the term of the patent subsequent to Dec. 25, 1980, hasbeen disclaimed 1 Claim. (Cl. 260-668) This invention is concerned withnew alkyl benzene hydrocanbons which are useful in the production ofsuperior synthetic detergents, and vw'th the preparation of thesehydrocarbons. More particularly, this invention is concerned with theproduction of alkyl benzene hydrocarbons having at least one nuclearsubstituted alkyl chain containing from 8 to 24 carbon atoms, said alkylchain having the structure of a methylene group attached between thebenzene nucleus and a highly branched alkyl group. Most particularlythis invention relates to a mono alkyl benzene hydrocarbon of the abovedescribed structure.

Illustratedin chemical notation, the new alkyl benzene hydrocarbons ofthis invention may be represented by the following general formula: RCHR wherein R is benzene and R is a branched, acyclic hydrocarbon group offrom 10 to 18 carbon atoms. The degree of branching of R is such thatabout 50 to 95%, preferably 50 to 80%, of the total carbon atoms in thealkyl group (including the methylene group) are in a straight chain ofcarbon atoms.

The alkali metal sulfonate salts of these alkyl benzene hydrocarbonshave now been found to be highly superior to other similar typedetergents known in the prior art. This is true not only with respect tothe washing properties of these detergents but also with respect totheir capacity to be removed in conventional sewage disposal plants.This the present detergents have been found to be substantially entirelyabsent from the eflluent from such a sewage treatment, having beenremoved by biodegradation, adsorption, and the like. This property is anextremely important factor in preventing the foaming which has beenencountered in rivers and streams into which the eflluent from sewagedisposal plants is discharged. It should be noted that it is surprisingthat both of these improvements are obtained at the same time byutilizing the present easily and cheaply prepared materials havingmolecular structures as above described.

The present invention will be more clearly understood from aconsideration of prior art commercial detergent materials made byalkylating benzene with polymers of propylene containing from 10 tocarbon atoms. These prior art detergent materials are the major onesused in the household detengents marketed today. These materials may berepresented by the following chemical formula:

R1 b-R. it

3,234,297 Patented Feb. 8, 1966 sist predominantly of tri and tetraalkyl substituted ethylene Thus, the alkyl aromatics obtained onalkylating benzene with this material possess in large part a trialkylsubstituted carbon atom adjacent and attached to the aromatic nucleus,i.e.

l. wherein R R and R are alkyl groups.

It is now known that these conventional commercial alkyl benzenesul-fonates having a trialkyl substituted carbon atom attached to thearomatic ring are particularly resistant to biological degradation bybacteria normally present in microorganism populations of activatedsewage sludge (and that they are not otherwise removed by adsorption,etc). Further it is known that severe foaming and frothing have occurredin many locations Where sewage disposal plants discharge their efiluentinto rivers and streams. It has now been found that the deter: gentmaterial of the type described in this invention is readily degradedbio-logically or is otherwise removed by the microorganisms normallypresent in this sludge and when processed in a sewage plant produces anetiluent from said plant having little or no tendency to foam.

The presence of, and the relative proportion of alkylatcd aromaticshaving a tri substituted carbon atom attached to the ring may beestimated by means of mass spectroscopy, nuclear magnetic resonance orinfrared spectroscopy. One means, that of mass spectroscopy, forestimating the presence and relative amount of ring-substitutedquaternary carbon in an alkylated benzene is by determining the ratio ofthe amount of mass 91 fragments CH (representing a methylene attached tothe ring) to mass 119 fragments with R and R each being a methyl group).For a large number of commercial alkylates, made by the alkylation ofbenzene wit-h tetrapropylene, this ratio is in'the order of 3.3 while incomparison, pure l-phenyl dodecane gives a ratio of nearly zero. A puresynthetic sample of 2- phenyl-Z-methyl undecane.

gave a ratio of 5.33. Another method for determining the nature anddegree of branching on the carbon atom attached to the aromatic ring isby the use of nuclear magnetic resonance. By this means, pure alkylatesconsisting of l-zphenyl dodccane give values of about 2.2 hydrogen onthe carbon adjacent to the ring (theory=2); 2, 3 or 4 phenyl dodecanegives values of about 1.25 hydrogen on the carbon adjacent to the ring(theory=1), and an alkylate made from commercial tetrapropylene shows0.25 hydrogen on the same carbon (theory for a quaternary carb0n=0.0).Deviations from theory are probably due to calibration errors.

It has now also been discovered that superior washing properties-may beobtained by utilizing a molecular structure wherein 2. CH group linksthe benzene ring to a branched alkyl material having 50 to 95% of the 3total carbon atoms in the longest straight chain of the alkyl groupmeasured from said methylene group. Althoughv it is not intended tolimit this invention by a particular theory, this improvement in Washingproperties may be attributed to changing the molecular volume of themolecule by obtaining a proper balance in the length of the longestalkyl chain measured 'from its point of attachment to the methylenegroup. It should be noted that this object isnot attained merely byutilizing a higher olefin such as pent'apropylene or a higher fractionobtained from tetra'pr'opyle'ne as the alkylation feed as has been usedin some commercial detergents. These detergents although superior inwashing properties to conventional tetrapropylene obtained materials arestill greatly inferior to the present invention detergents. Thus, it istheorized that just the right balance of solubility and emulsifyingproperties are obtained in the present product detergent.

A wide variety of methods may be used in preparing the new alkylaromatics of the present invention. -A preferred method utilizes ahighly branched material such as a tetrapropylenefraction of U.O.P. typepolymer as the starting material. Olefin polymers suitable for use asfeeds'for this process may be obtained from a process as described inUS. Patents 2,486,533 and 2,695,326 both of which deal with polymers ofC to C normal olefins herein termed U.O.P. type polymers. A fraction ofsuch polymer containing between 9 and 18 carbon atoms to the moleculemay be used but a C to C out which is predominantly C is preferred. Morespecifically the polymers of butene-l and butene-Z and their copolymerswith propylene in addition to homopolymers of propylene, e.g.trip'ropylene and tetrapropylene, are preferred. Of these tetrapropyleneis most preferred. These materials may be either (a) oxonated to inserta reactive additional carbon atom in the molecule which is then reactedto form the methylene link between the aromatic ring and the alkyl groupor '(b) converted to a halide which is then reacted with a material suchas ('1) toluene in the presence of an alkali metal or (2) with an alkalimetal benzyl material, or a Grignard reagent prepared from a benzylhalide to produce a compound having the desired methylene link "betweenthe aromatic ring and the alkyl group.

The following specific methods of preparation of the desired alkylbenzene hydrocarbons of this invention may be utilized.

(1) A fraction of polymeric U.O.P. olefin as above described, forexample, a tetra'propylene or pentapropylene, is subjected tohydroformylation or x0 process to produce an aldehyde having one morecarbon atom than the olefin starting material, e.g. tridecyl orhexadecy'l aldehyde. Methods for carrying out this reaction aredisclosed for example in US. Patent 2,636,903. 'Thus, in general,temperatures of 150 to-450 C.,e'g. 300 C., pressures of 1500 to 4500p.s.i.g., e.g. 3000 p.s.i.g., 0.5 to 2.0 molar proportions of .CO to Hbut preferably equal molar proportions of these materials, and from 0.8to 2.0 moles, e.g. 1.2 moles, of CO and H per mole of olefin feed-alongwith 1 to 3 wt. percent of a cobalt catalyst, e.g. cobalt oleate permole of olefin feed are used. The resulting aldehyde afterdecobaltingwith steam is reduced to a primary alcohol, also as describedin the above'patent, by contacting it with 5,000 to20,000, e.g. 10,000ft. per bbl. offeed of hydrogen at temperatures of 300 to 500 C.,pressures of 2500 to 4500 p.s.i.g. and in the presence of any of thehydrogenation catalysts well known to the art. Suitable catalysts arenickel, copper chromite, cobalt, sulfactive catalysts of the type ofoxides and sulfides of tungsten, nickel, molybdenum and the like, eitheras such or supported on a carrier, e.g. Raney nickel. The alcohol isthen converted to a monohalide by contacting it with a halogen acid,e.g. HBr at temperatures of 20 C. to 200 C., e.g. 120 C.,and pressuresof l to-2 atmospheres,.e.g. 1 atmosphere. The h ide i then mixed with amonoh lo benzene, e.g.

bromobenzene and is subjected to a Wurtz-Fittig reaction utilizingmetallic sodium and temperatures of 20 C. to C., e.g. 35 C. to obtainthe alkyl aromatic product. The molar ratios of monohalo benzene toalkyl monohalide for this reaction may be in the range of 0.8 to 1.5,e.g. H0 and the molar ratio of metallic sodium to monohalo benzene maybe in the range of 2 to 5, e.g. 3.

It should be noted that the extent of the branching of the acyclichydrocarbon group attached to the methylene group in the alkyl aromatichydrocarbon produced as above described can be calculated as follows(where '[l'l decyl oxo" alcohol is used as the starting material). If;is known (from a combination of physical methods such as infraredanalysis and mass spectroscopy) that the in: decyl alcohol commerciallyprepared by oxo process consists primarily 'of2,4,6,8-tetramethylnonanols. Therefore, since the coupling of thetetramethylnonyl bromide to the benzene group occurs at the carbon atombonded to the bromine atom, the longest straight chain of carbon atomsattached tothe benzene group contains 9 carbon atoms. Thus,'9 of the 13,or 70%, of the carbon atoms in the alkyl group of the alkyl benzenecompound are in a straight chain of carbon atoms.

(2) An oxo aldehyde prepared as above described, e.g., prepared from atetrapropylene fraction, is reacted with the Grignard reagent of abenzene halide, e.g. the Grignard reagent of bromo benzene attemperatures of 20 C. to 40 C., e.g. 15 C., to obtain a condensationproduct. The molar ratios of Grignard reagent of a benzene halide to oxoaldehyde may be in the range of 1 to 2, e.g. 1.2:1. The condensationproduct obtained is then hydrolyzed at temperatures of 0 to 50 C., e.g.20 C., to yield the secondary alcohol. This alcohol isthen dehydrated tothe olefin at temperatures of 100 to 300 C., e.g. C., in the presence'of a solid catalyst such as alumina, thoria, titania, aluminumsilicates, sodium bisulfate or aqueous sulfuric acid, etc., e.g.alumina. The olefin so produced is then reduced by hydrogenation attemperatures of -20 to 100 C., e.g. 35 C., in the presence of ahydrogenation catalyst such as platinum, palladium, or nickel, e.g.platinum, to the desired alkyl benzene. Although in the steps involvedabove such as coupling of a Grignard reagent with an aldehyde,hydrolysis to the alcohol, dehydration to the olefin and bydr-ogenationof the olefin certain procedures have been described, it is of coursecontemplated that the other alternate-methods described in standardtexts of organic chemistry may also be use-d. This is true also of thesteps in the preparations described below.

(3) An oxo derive-d alkyl halide produced as described in Method ofPreparation 1 above, e.g. prepared from a tetrapropylene fraction isreacted with a substituted benzene wherein one of the hydrogen atomsattached to an aromatic ring carbon atom 'is replaced with an alkalimetal, forexample, phenyl sodium-or phenyl lithium. The desiredcondensation is obtained at temperatures of l0 to C., e.g. 35 C.,utilizing molar ratios of the alkyl halide t-o alkali metal substitutedbenzene in the range. of 0.8to 2.0,e.g. 1.221, to obtainthezdesiredalkyl benzene. v

(4) An oxo aldehyde prepared as described in Method of Preparation 1above, e.g. prepared from a tetrapropylene fraction, is oxidizedto theacid at temperatures of 20 to 100 C., e.g. 60 C., .utilizing 0.5 to 3moles, e.g. 1.2 moles, of an oxidizing agent such as alkalinepermanganate, hydrogen peroxide, organic peracids, silver oxide, andmolecular O e.g. hydrogen peroxide. The product acid is converted to anacid chloride-by means of PCl or thionyl chloride, e.g. 'PCl and is thenreacted with benzene in the presence of a catalyst such as aluminumchloride, ferric chloride, etc., e.g. aluminum chloride at temperaturesof 0 to80 C., e.g. 20 C., utilizing molar ratios of benzene to acidin'the range of 2 to 10, e.g. :5::-1, :to give a carbonyl link betweenithebranched alkyl group and the aromatic ring. The carbonyl group linkin this product is then reduced to a methylene group by means of zincand a strong acid, i.e. HCl, or by means of hydrazine and alkali, i.e.NaOH, or by means of hydrogen in the presence of a catalyst such asnickel, palladium or platinum, e.g. platinum, at temperatures of 20 to100 C., e.g. 50 (1., and pressures of atmospheric to 50 atmospheres,e.g. 5 atmospheres, to give the desired alkyl benzene.

(5) The acid described above in Method of Preparation 4, e.g. preparedfrom a tetrapropylene fraction, may also be obtained by saponificationof a lower alcohol ester obtained directly by performing thehydroformylation reaction in the presence of a (E -C monohydric alcohol,e.g. methanol, as described in US. Patent 2,688,627. Thus, temperaturesof 100 to 200 C.,e.g. 150 C., pressures of 2500 to 4000 .s.i.g., e.g.3000 p.s.i.g., 1.0 to 3.0, e.g. 2.0, moles of CO per mole of olefin, 1to 10, e.g. 5, moles of alcohol per mole of olefin and 0.1 to 5.0 wt.percent of a cobalt catalyst, e.g. cobalt oleate (calculated as themetal and based on the olefin) are used. The resulting carbo alkoxyderivative after decobalting is then converted to its correspondingcarboxylic acid by hydration with a moderately dilute acid, e.g. 20 wt.percent sul- *furic acid, used with or without the addition of an agentcapable of depressing the interfacial tension such as mahoganysulfonates, Twitchell agents and the like. Alternatively, the ester maybe saponified in conventional manner by means of an excess of alkali.The acid is then reacted as previously described in Method ofPreparation 4 to obtain the desired alkyl benzene.

(6) An aldehyde of the type described above in Method of Preparation 1may also be prepared by a combination process in which the monomericolefins are fed to the oxo process and hydroformylation and dimerizationoccur at the same time. Such a process is described, for example, in US.Patents 2,820,067 and 2,811,567. The process is operated by passing theolefin, hydrogen, CO, a cobalt carbonylation catalyst and a reactionmodifier such as a zinc comprising material, e.g. zinc oleate into acarbonylation zone operated at temperatures of 200 to 400 C., e.g. 375C., and pressures of 1500 to 4500 p.s.i.g., e.g. 3000 p.s.i.g. The H andC are supplied in a ratio of from 0.5 to 2, e.g. 1, volumes H per moleCO, while the cobalt salt is supplied to the extent of 0.2 to 0.5, e.g.0.2 wt. percent, calculated as metal on olefin feed, and the zinc to theextent of 0.05 to 0.5, e.g. 0.1 wt. percent, again calculated as metalon olefin feed. Reaction times are 2 to 48, e.g. 8, hours. The aldehydeformed is then decobalted to remove suspended cobalt and reactionmodifier components. The aldehyde is then reacted to obtain the desiredhydrocarbon product by any of the methods previously described. As anexample of this modified 0x0 process, pentene may be oxonated in thepresence of modifiers, for example, zinc salts, so as to obtain a dimeralcohol having the general composition of C H CH(CH OH)(C H In simi larmanner a primary tetradecyl alcohol may be made by oxonating eitherhexenes made by catalytic cracking process or hexenes obtained bypolymerizing propylene, to give an aldehyde having the generalcomposition 11 2 i r ra) (7) A fraction of polymeric U.O.P. olefin asabove described, for example, tetrapropylene or triisobutylene isconverted to a halide by reaction with a halogen acid, e.g. HCl, attemperatures of 20 C. to 20 C., e.g. 0 C. and pressures of 1.0 to 5atm., e.g. 1.0 atm, The resulting alkyl halides are then reacted witheither:

(a) 0.1 to 1, e.g. 3, moles of toluene per mole of alkyl halide in thepresence of 1 to 2 e.g. 1.2, molar proportions of an alkali metal, e.g.sodium, based on alkyl halide, at temperatures of 20 to 110 C., e.g. 50C.; or

(b) 0.5 to 1.5, e.g. 1, mole per mole of alkyl halide of an alkali metalbenzyl product (produced by treatment of a benzyl halide with an alkalimetal or of toluene 0.8:1 to 2.25:1, a 1:1 ratio being suitable.

with reagents such as potassium-sodium oxide) e.g.

sodium benzyl, at temperatures of 0 to 120 C., e.g.

50 C., to give the desired alkyl benzene hereinbefore described. Itshould be noted that in the reaction with the halogen acid to obtain thealkyl halide that conditions may be varied to obtain either normal orabnormal Markownikoif addition products. If lengthening of the longestalkyl chain is desired, abnormal Markownikoii addition should bepromoted by the use of oxygen, light, peroxides, or ganic acid promotersand free radical initiators in such a reaction. In general abnormalMarkownikofi addition is preferred.

The alkyl benzenes are then sulfonated by conventional means to obtainthe desired alkyl aryl sulfonic acids for detergents, e.g. by contactwith an excess of concentrated sulfuric acid. The sulfonation may becarried out at temperatures up to 50 C. The acid concentration ispreferably at least 97%. Acid up to 100% concentration and oleum,containing up to 20 wt. percent S0 or higher, may be employed. Withhigher acid concentration, lower reaction times are required, e.g. about8 hours with 98% acid and one hour with 100% acid. Volume ratios ofsulfuric acid to hydrocarbon may range from The larger the ratio, themore inorganic sulfate will be present in the product, followingneutralization. In many cases, the inorganic sulfate is a desirableconstituent of the finished detergent composition.

The sulfonation product mixture is preferably freed, e.g. by decanting,from unsulfonated hydrocarbons. The mixture is then neutralized, thesulfonic acids being thus converted to sulfonic acid salts and theexcess sulfuric acid into sulfate. The neutralization may be carried outwith any base or basic reacting inorganic or organic substance. Thus, toproduce sodium sulfonates, aqueous sodium hydroxide or sodium carbonatesare suitably employed. Other alkali metal, alkaline earth metal,ammonium or amine salts may be similarly produced from the correspondingbasic compounds. The neutralization is generally carried out by contactwith the aqueous solution at temperatures of from 20 to 100 C., thosebetween and C. being preferred. The relative amounts of oil soluble andwater soluble detergents obtained is of course dependent upon thedistribution or amounts of the various chain lengths of the alkyl groupson the benzene ring and also on the average chain length of these alkylgroups.

Neither the methods used for preparation of the desired alkyl benzenehydrocarbons, nor the method for preparing the detergent materialsdescribed above, nor the examples which follow are to be construed aslimiting the methods which are suitable for the preparation of thesematerials, since other methods for accomplishing the desired end asdescribed are known in the art.

EXAMPLE I.TRIDECYCL BENZEN E A commercial letrapropylene fractionboiling in the range of 180 C. to 220 C. made by polymerizing propylenecontaining a small amount of butenes Over a phosphoric acid onkieselguhr catalyst, was oxonated in the presence of 2 Wt. percent of acobalt oleate catalyst utilizing 1.3/1 ratio of H /CO, a temperature of150 C. and a pressure of 3000 p.s.i.g. The resulting aldehyde wasreduced to a primary alcohol with hydrogen with the aid of a nickelcatalyst and the alcohol after fractiona tion boiled at 173 to 176 C. ata pressure of 51 mm. Hg. The alcohol was converted to the bromide bycontacting it with anhydrous HBr at a temperature of C. and atmosphericpressure. After purification and fractionation, the tridecyl bromideboiled at 75 to 78 C. at a pressure of 0.8 mm. Hg.

Two hundred and sixty-three grams of the tridecyl bromide were mixedWith 157 grams of bromobenzene and subjected to a Wurtz-Fittig reactionusing 60 grams of sodium at a temperatureof 35 C. Afterfisolationand'refrac'tionation, "an alkylate was'obtained which boiled showed onanalysis a carbon content of 87.71% and "the end point. 'fonate wassubstituted for the sodium tridecyl benzene cle-a'nsingjand the colordisappears in the foamjust before A conventional 'tetrapropyl benzenesulsulfonate and was compoundedin the same concentrations as above andwas tested for dishwashing in comhydrogen cont t f 12 29%, Analysis fthe tridecyl parison with the product made in Example 11, giving thebenzene by' means of a high temperature mass spectromeresults shownbelow in Table I.

ter showed the following composition: TABLE 1 1s11w ASKING TESTS PercentC benzene 1.02 d Ndil iber C12 benzene 25.40 not s lishes C benzene60.85 Ion Washed C14 benzene 2 'lridecyl benzene 0.,01 "10 12 The ratioof the mass peaks at 119/91 equaled 0.100. gg y 'g g a g m 8:3? 3% Thislatter ratio as discussed. previously indicated the 15 Do 0. 03 15-16high proportion of the alkylate which is of the A V EXAMPLE IV type as ce to i d' m CH n An additional amount of the sodium benzene s'ulfonateR2 prepared as described above was again compounded into I] a detergentalso as described above and'tested in comparison with a number of other'detergents'in a standard "R1 cloth washing test. From the dataobtained, presented types below, it'can be'seen thatj'again'thismaterial showed much improved results over the prior art tetrapropylben- EXAMPLE BENZENE zene commercial similarly built detergent material.In I the table US. stands for U.S. Testing Company, Dry Fifty grams ofthe tridecyl benzene prepared in Exam- Soiled Cloth; and TE. stands forTestFabric, Inc., 'ple 1 were sulfonated with 70 grams of 20% oleum inOily Soiled Cloth.

TABLE II [Cotton detergency140 F.]

Concentration 0.03% 0.05% 0.10%

Water hardness 2 Gr. 8 Gt. 8 Gr. 8 Gr.

sen type U.S. T.F. U.S. T.F. U.S. m. U.S. 1 .1

Sample VAR tridecylbenzene detergent 11.6 23.3 8.9 23.2 10.6 21.4 10.022.7 Commercial sold similarly built tetrapropylbenzene detergents 5.711.7 5.1 10.2 8.0 12.9 10.6 16.2

cloth.

. k p H Wt. percent fiSodiurn 'tridecyl benzene sulfonate 15fSodiumsulfate 40 "'Sodiummetasilicate (a'nhyd) 5 Sodiumtripolyphosphate 30 Sodium tetrapyrophosphate 1O The test consisted inwashing 8 inch white dinner plates,

havingjlJS grams of a hydrogenated vegetable shortening distributed overthe' surface, in 6 liters of detergent solution made up with 2 grainshard Water in a dishpan weight percent based on the active ingredientcontent until r oarn disappearance occurred. A trace of acolloidaldye,'dispersed in the shortening, indicated lack of AR-Inereasein percent reflectance after washing compared to unwashed, soiledEXAMPLE V.BIOLOGICAL DEGRADATION A sample of the sodium tridecyl benzenesulfonate prepared as described in Example II was tested in comparisonwith a commercial detergent sulfonate prepared by alkylating benzenewith tetrapropylene (the commercial detergent having present also 19 wt.percent of sodium sulfate and water). The equipment consisted of twobanks of 4 glass columns each about 3 ft. high and 2 inches in'diameter.The columns were packed with beds of Nottingham granite on whichcolonies of bacteria had been developed over a period of weeks. In eachcase a solution of the tW0 detergents to be evaluated (about 1 liter ofconcentration 10 to 50 ppm.) together with a standard nutrient for thebacteria (m alto-peptone) was added to each column and was circulatedslowly around the system by means of an air pump. This insured that thecolumn remained aerobic, the solution being circulated through thegranite bed about seven times an hour. This type of submerged digesterfsystem is reasonably representative of the percolating filter type ofcommercial sewage plant which, according to Government reports, is usedat sewage works serving about 22 million of the population of the UnitedKingdom.

Samples were drawn from the columns after 15 minutes and after 1 hour, 2hours and 24 hours. The quantity of detergent remaining in each samplewas extracted with chloroform and the intensity'of blue color developedwith methylene 'blue' was 'measured by a photoelectric absorptiometer inaccordance with the standard method to obtain the percentage ofdetergent remaining in the sample.

The following data Were obtained and are shown in the following table.

TABLE III [Initial concentration 3060 p.pr1n.]

Wt. percent degraded alter Initial Detergent cone,

p.p.m. 15min. 1 hour 2 hours 24 hours 51. 8 54 71 79 96 Sodium trideeylbenzene 51.8 55 71 81 99 sullen-ate. 55, 7 58 82 1 52. a s9 68 88 50. 967 76 87 94 50. 17 31 2 9 23 Commercial tetrapropyl g benzene sull'onate(con- 8 18 20 2g 53 taining also 19 wt. percent 0 26 21 34 32 sodiumsulfate and water). 34 32 51. 5 27 18 38 It is to be understood thatthis invention is not limited to the specific examples, which have beenoffered merely as illustrations, and that modifications may be madewithout departing from the spirit of this invention.

What is claimed is:

A hydrocarbon mixture suitable for sulfonation to form detergentsconsisting essentially of monoalkyl benzene hydrocarbon having thegeneral formula RCH 10 R wherein R is benzene, R is a tetrapropyleneradical and the degree of branching of R is such that about to of thetotal carbon atoms in the alkyl group (including the methylene group)are in a straight chain of carbon atoms.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCESDyson, A Manual of Organic Chemistry, Vol. I (1950), page 72, pub. byLongmans, Green & Co.

Egloff, Physical Constants of Hydrocarbons, published by Reinhold Publ.Co. (N.Y.), 1946 (page relied upon).

DANIEL E. WYMAN, Primary Examiner.

LEON ZITVER, MILTON STERMAN, ALPHONSO D.

SULLIVAN, Examiners.

